In many technical contexts, there is a need for displacement apparatus which collect articles from one position and move them to a new position, and in which the displacement takes place in one and the same plane (for example in a vertical plane). In such instances, the new position is often offset in both the vertical and the horizontal plane in relation to the collection position. In such physical applications, there is also a need for equipment which permits articles to be displaced substantially in one linear movement, for example in a vertical direction, in order to be removed from or deposited in spaces with restricted accessibility. Such needs exist, for instance, in operations in which articles are moved between mutually subsequently disposed baths for surface treatment (dip painting, galvanizing etc.). and also in many other fields of application in which, for example, packets, pallets or crates are stacked on or nested in one another.
It is previously known in this art to employ, for the above-outlined purposes, such equipment as overhead traveling cranes which run along a track and in which a lifting device may, using a cable, move up and down so as to realize the vertical displacement of the articles, while the horizontal displacement of the articles is brought about when the traveling crane moves along its track.
There are also similar solutions in which overhead traveling cranes with guide-steered lifting devices, sometimes also designated column traveling cranes, run along a track in a corresponding manner and the articles are moved along the track in the horizontal direction while the lifting device caters for the vertical displacement.
The above-described prior art solutions suffer from the drawback that, in certain of the embodiments, the articles, together with their lifting devices, may easily begin to swing pendulously in conjunction with their movement in the horizontal direction. In particular in articles of great mass, these problems are accentuated, since the moments of inertia and kinetic energies generated assume considerable proportions.
A drawback inherent in overhead traveling cranes with guide-steered lifting devices is that the columns are bulky and require considerable space, present obstruction when work is in operation and entail a risk for personal injuries, for example contusion injuries.